[jonsk2514]

I have started routing. For practice I am going to make a small box that will mimic the speaker cabinets I am making.

As I noted previously I have not worked with MDF before. It actually cuts pretty well. The router bit does leave a bit of feathering. Given that this will be a glued surface I suspect this will be ok. I am starting with a small Craftsman router table with a 1 hp Craftsman router mount in it.



Made in USA

I first made 3/8” deep cuts in the side and end pieces using the table saw. I figured this would make the actual routing less critical.

Sides:


Top and bottom:


The actual routing went well. I used a scrap piece to set the router height and then went to work.

Long side piece routed. It did have a piece pop off but it is hard to see where.


I tried making a smaller cut but the end piece still popped. This happened no mater how slow I went.



I think I have 2 choices.... use a piece of wood clamped to the trailing edge of the piece I am routing, as was suggested, or just leave it and let the glue and clamping “fix it”; the pieces do pop of pretty cleanly.

The final test/practice box, dry fit together.  This represents the back, 2 sides, and the top and bottom.



The outside edges came out well with a touch of overage that would need to be trimmed off, if this was the actual cabinet.  There is one inside edge where there is a gap, which I will look into a little.  It didn’t close up with the clamps, so I suspect that I miss a little when I did the relief cut on the table saw.

Overall, this was quite a success.  It took me about an hour to cut the 5 pieces and do the routing.  Much quicker than I thought it would take and the dry fit assemble looks good.  I am pleased with how the router table worked.  I was hoping it would work as the dust collection on it is really good.  I am thinking that I may have to get a roller to support the longer pieces, but that is a minor bother.

[diyman]

Nope, I am not one to follow conventional wisdom. 

That is certainly true, and you can build it anyway you want.  However, you have been touting this thread as a tutorial for others to follow and I have to take strong exception to that idea.

In some respects you are doing things in very unconventional ways.  So I would caution anyone from using this as a tutorial.   Particularly, since it's coming from someone with admittedly a limited amount of experience in woodworking.

[jonsk2514]

That is certainly true, and you can build it anyway you want.  However, you have been touting this thread as a tutorial for others to follow and I have to take strong exception to that idea.

In some respects you are doing things in very unconventional ways.  So I would caution anyone from using this as a tutorial.   Particularly, since it's coming from someone with admittedly a limited amount of experience in woodworking.

And you may be right in the long run...

And I respect your comments.

Maybe I should have said this is a thread of “other thoughts”.... 

Still, I would like to think this will come together in the end.  If nothing else I hope the discussion here provides others with thoughts about how to come through a project such as this.  Not just my thoughts, but with the thoughts of others who post here.

I am making an effort to record my thoughts and decisions so others can see they may not be alone in “why this, why that”.   My intent was not for this to be a tutorial as to how to build one of these.  I am not qualified to do that.  And there are plenty of threads here on AC that clearly show the right way to make these and other speakers.  My intent is for this thread to be a discussion as to how a novice comes through the build of one of these so others can see they can do it too.

I intend to show experiments/mockups/practices I have done so others understand how I have gotten to where I am.  I think it is good for someone who is hesitant to do one of these to see what someone else’s thoughts are for doing this.  I also believe that it is important for a novice to understand the value in practicing things and to mock them up before cutting chips on a final product.  If something i do is a failure, I will say so.
By me making these posts may also encourages others to make comments, such as your, so people see different points of view.  Surely, I don’t consider mine to be “right” .

Rest assured, I believe that your input and comments and those of others are in integral part of this being being what this thread should be.  I have a better understanding of the glues and adhesives because of this input.  So, please continue to follow and comment.

[jonsk2514]

There is a lot to be said for practicing, if you are like me and are without a lot of experience with these things.  In this case, as I said, I have little experience doing routing and never on the MDF.  Based on the little experience I do have with wood, I first cut a groove in the MDF with the table saw.  This had helped me in the past to prevent chipping wood pieces (maybe also due to dull bits ).  I thought the same would be of a benefit with the MDF.

Nope!  I found that the relief cut was actually causing the chunking I was having.

I took another look at the box I made (see above) and noticed that the chunks that came out also left a depression, which was not good for fitup.  The depression resulted in gaps in the fitup at the edges, which I thought were larger than what the glue would fill and these would likely be unsightly in the end.

I went back to the router with some scrap pieces of MDF and tried just make the full cut with the router.  I have a brand new bit in it, and it did a nice clean cut. 

No chipping or chunking.  Problem solved!  No relief cut prior to routing the MDF...

Another note, I left the setup of the router on the table the way it was when I had done the routing after doing the relief cut.  So the practice I just did resulted in a bit of an undersized cut.  This left room to do the table saw relief cut (now a cleanup cut?) after doing the routing.  This, too, worked really well and cleaned up “oops” that seem to always occur when I run a piece on the router table.  These are “oops” in the direction of “in and out“, “not up and down”, so the cleanup cut works week to correct this.  This is probably a result of me not doing well pushing it through, along with not having the world’s best table.  I suppose I could do this routing with an edge guide and hand holding the router, but I am finding the table routing along with the cleanup cut on the table saw to be quick and accurate.  Plus the table allows for great dust control.

With this done, I have a bit more confidence in going forward with the cabinets.

[jonsk2514]

For reference, I found these threads that cover topics helpful to me:
https://www.audiocircle.com/index.php?topic=100369.60
This includes discussion about magnetics and other stuff.

https://www.audiocircle.com/index.php?topic=128392.0
This covers the build of a set of X-MTMs

A question to anyone...

The second thread shows the X-MTM cabinets without the fronts on to facilitate installation of no-Rez and other stuff. 

Is there a preference with these as to which panel (front or back) that gets left off?

[Peter J]

A question to anyone...

The second thread shows the X-MTM cabinets without the fronts on to facilitate installation of no-Rez and other stuff. 

Is there a preference with these as to which panel (front or back) that gets left off?

Dealer's choice, methinks. I'd probably do baffle last, just to minimize the possibility of it from getting barked up some way.

[mlundy57]

Dealer's choice, methinks. I'd probably do baffle last, just to minimize the possibility of it from getting barked up some way.

+1  I do the front baffle last.

[jonsk2514]

Thanks. 

I was leaning to doing the front last.  I had a few thoughts why doing the back last might be good, but nothing overly compelling.

[jonsk2514]

A trip to the Dark Side

As a way to practice and to see what I am up against, I have built a miniature of my speaker cabinet the way I plan to build it.  I have not yet glued it together, but it has been fully dry fit will success.  I have learned a lot from this...

I tried to cut external pieces oversized and internal pieces undersized.  I achieved only moderate success with this.  What I found in the dry assembly was that a 1/32nd over and 1/32nd under seems to come out pretty much dead on...  So I need to be careful with this and to get enough difference so I don’t have a net underage.

I want the sides and top and bottom to be the “controlling” pieces so all of those joints are tight.  Then I want the inner recess of the front panel to just fit into the “box” formed by those other pieces.  Same with the back panel.  This may mean that some of the panels may need to be trimmed a bit to make this all happen.  This will be done based on the way it looks in the dry assembly.

Overall the test cabinet took less time and effort than I thought it would.  Overall, it is quite tolerant of little imprecisions.  So, I can relax a bit and not sweat the small stuff.

I did some more routing and then trimming of the relief using the table saw.  This continues to work well.

I need to do better at marking the panels as to what goes where and orientation.

I should have made this test box before I cut any of the full size panels...    I expect they are all OK.  Mostly I hope the ones that are intended to have overage, have enough overage.  Otherwise, the cabinet may be a “hair” smaller than planned...

The trip to the Dark Side seems to be working out...

Here are the side panels with the layout started for the addition of the quarter rounds.



One thing I figured was that the location of the braces will be controlled by the recess lip and where it meets up with the back panel.  So I did the location mark measurement along that edge and used a square to draw the location line for the quarter round.

I then transferred the layout from each side panel to the back panel and then drew a line on the back panel using those transfer marks.  I hope to use these for reference to locate the braces while gluing but before the sides are in place.



The 3 panels with layout lines and the quarter round all cut.



I used Titebond III to glue the quarter round to the panel and then used a brad nailer to hold the quarter round in place while the glue dried.



I then used a spacer to locate the opposing quarter round.  I happen to have a piece of 3/4” square tube that I used.  This could have been anything that was 3/4” in size.  I wrapped a piece of thick tape on the bottom and the sides.  This was to ensure some small clearance between the quarter round and the brace that will later be fit within.

Spacer with tape:



Fitting quarter round with spacer.  Again, these are glued and tacked in place with the brad nailer.



All of the pieces before the dry fitup:



The assembly looking in from the backside:



One of the things I found in an earlier dry fitup was that the back panel was oversized, even though I cut it to what I thought was undersized.  Here is the back panel placed on the sides/top/bottom assembly.  What you see is about 1/32nd overage.  But, this was enough to cause gaps in the fitup of the sides/top/bottom pieces that would not press out with the clamps.  This was correctable with a small trim on the table saw.  But it was a heads up for me that there may be pieces that will need to be customized to fit correctly.

[jonsk2514]

Has anyone had any experience with the TiteBond Quick & Thick wood glue?

http://www.titebond.com/product/glues/d1b48beb-7d60-4ce7-b57b-6bf19351778b#

They say it is a new product.  It has a set and workable time that is similar to the TiteBond II, but seems that it would be good for vertical surfaces.

[Sonicjoy]

Boy that is some rough and soft looking MDF. No wonder you have trouble with chunks breaking off. Next time look for some premium quality MDF You will find it much better to work with.

[mlundy57]

Has anyone had any experience with the TiteBond Quick & Thick wood glue?

http://www.titebond.com/product/glues/d1b48beb-7d60-4ce7-b57b-6bf19351778b#

They say it is a new product.  It has a set and workable time that is similar to the TiteBond II, but seems that it would be good for vertical surfaces.

Yes, I use it and vertical surfaces is where it works best. However, it does not have as much open time as the II or III.

[jonsk2514]

That is good to know...  Thanks!

[diyman]

From the photos it looks like you are not getting a square edge on the panels.  Table saw may still need more adjusting.

[jonsk2514]

I could do a plain butt joint for the braces, as was suggested above, along with the comment this will be plenty strong.

[diyman]

I could do a plain butt joint for the braces, as was suggested above, along with the comment this will be plenty strong.

Only if you are able to cut the ends square and the braces to a precise width.  And that width may vary from cabinet to cabinet or even at different locations within the same cabinet.

The best approach is to cut dados to accept the braces with a router.  Need to make the dado width just a hair larger than the thickness of the braces.  If too tight assembly may be difficult and you will have to pound it together with a rubber mallet after applying glue.

Have you watched the YouTube videos I mentioned previously about how to cut precise width dados?

[jonsk2514]

I think I went overboard on buying glue:


    

I even got sucked into the “special” Titebond brush (or 2)...

This all started with me looking into the Titebond web page to see what was available.  A couple of the glues I had on hand from a while back and I had picked up the Titebond III as was used in one of the videos.  I started with a simple curiosity question...  Which is the worst for runs when put vertical.  So a dab of Titebond Original and III went on a piece of MDF.  It was tilted up on edge and the the III won the contest... It ran immediately.

Then came the thought as to how strong a butt joint would if it was made with no clamping force.  The web page suggests that 100 to 200 psi clamping pressure is needed for bonding various woods.  This would be 1000 to 2000 lbs of clamping force for every 10 in^2.  With 7 braces (figuring each is about 10^2 of contact with the side panels), it would take 7000 to 14,000 lbs of clamping force to make this work...  That ain’t happenin’... Or did I miss read the web page?

At any rate, I stuck a small of MDF into each dab of glue I had and hand pressed the pieces just enough to get the glue to come out the edges.  After a day of drying I broke off each of the pieces I had glued onto the 1st piece.  I was a bit surprised to see that the weakest part of all of this was the MDF.



At the bottom of this picture you can see on the ends of the the glued pieces where the MDF was ripped out.  A really odd thing was that the piece that was glued with the Titebond III was the easiest to break off.  Maybe the MDF under it wasn’t as strong there as it was under the other piece?

At the top of this picture, I tried the other 2 glues; the Quick & Thick and the Titebond II.  As you can see, I was not able to break the pieces off without the MDF just totally separating.  While I would guess this type of separation would be unlike in an actual assembly if it was pulled on with any amount of force.  It seems more likely, if the joint was pulled on, the surface of the MDF would pull off like it did with the first two glue joints I made.  It also seems that glue makes for a quite strong bond even without clamping, which should work well enough for the braces.  The braces have a little clearance to the side panels and to the back panel and likely vary a bit on width.  Having a reasonable bond even without clamping, will make clamp less critical for the braces and I can concentrate on having strong clamping to make up the joints of the remainder of the cabinet.

I liked the Quick and Thick and I think it will be a good choice for the bracket assembly.  Next I liked the Titebond Original and the Titebond II.  I know the work times are short with all of these.  I think I can stage the assembly in a way to accommodate this...  We shall see.

[diyman]

Are you sure that is really MDF?  It looks more like some sort of particle board.

[jonsk2514]

Are you sure that is really MDF?  It looks more like some sort of particle board.

Hmmmmm.....

Can you tell the difference



And I looked through the trash to find the tag...
But didn’t find it...

This may not be the highest quality MDF, but it is what is sold around here.  And it is likely what any other amateur will to be able to get their hands on.

Please, feel free to comment about my work and how I approach this project.  Clearly you have expertise well beyond that of which I or any other amateur might have.  That expertise is of interest to me.  But, also, please be really careful on your choice of words when forming a question such as this.  It might come across as calling someone “stupid”.

[diyman]

I'm not the only one to question your material.  Sonicjoy did the same thing a few posts above.  I don't know what you have, but it does not appear to cut or perform in the same way MDF usually does.

However, if you are so sensitive that questions like that bother you, then perhaps it would be better for others to be providing help to you without me.